On a flight across the ocean your plane crash lands on a remote island with no one around to help. Everyone survives but has amnesia ( memory loss ), so no one can remember the date. Everyone's belongings were destroyed when the plane crashed. How could you figure out roughly what month it is ?
Once it reaches night and since you're stranded on an island, you should check the constellations. If the stars are visible and a constellation is visible, it is summer. If the stars aren't visible, it's winter